| The treatment of copper bearing gold ores has always been a technical problem.High grade copper bearing gold ores are mainly treated to recover gold and copper at the same time by flotation,which are separated in the smelting stage.When the gold and copper grade of copper bearing gold ores are very low,it cannot be solved by flotation,and then will be usually treated by cyanide heap leaching method.Some copper reacts with cyanide to form copper cyanide complex in cyanide leaching.This results in the competition with the gold cyanide leaching and leads to not only increase the consumption of cyanide,but also to decrease the gold recovery rate.The copper cyanide complex is absorbed by activated carbon in the process of carbon adsorption and occupies a large number adsorption space of activated carbon,affecting the adsorption of gold and the subsequent desorption-electrowinning process.Based on the previous research,low grade copper bearing gold ore of the Zijinshan Gold Copper Mine as the research object,the cyaniding test and the heap leaching industrial test for copper bearing gold ores and adsorption process of the copper bearing rich liquid were studied in the second gold beneficiation plant of Zijinshan Gold Copper Mine.Through the direct cyanide test of copper bearing gold ore,it is found that increasing the amount of sodium cyanide can effectively increase the leaching rate of gold and reduce the gold grade in tailings.When the content of copper was 0.078%and free cyanide concentration was increased to 5/million,the gold grade in tailings was decreased to 0.1 g/t and was acceptable.In the heap leaching industrial test of copper bearing gold ore,the free cyanide concentration was improved quickly to ensure enough cyanide for the gold quick leaching at the initial stage.The leaching time of copper should be shortened with rapid leaching of gold.the gold grade of heap leaching tailings and the recovery can be controlled in 0.109g/t and 79.81%by controlling the free cyanide concentration less than 2.5/million and keeping low leaching level of copper ion In later period.In the study for the adsorption process of copper bearing rich liquid,the adsorption rate of gold was more than 80%when the free cyanide concentration of the adsorption solution was controlled more than 2.6/million and the concentration of copper ion was more than 200mg/l.In the removal of copper from deficient liquid,the bleaching powder with 60 times mass ratio was used to remove cyanide and copper.The copper ions was reduced from 370mg/l to 4.5mg/l,will not affect the gold ions.the reagents cost was controlled in 13.3 yuan/ton of water.The 50%hydrogen peroxide with the amount of 7g/l was used to remove cyanide and copper,copper ions can be reduced from 229mg/l to 11.3mg/1,will not affect the gold ions,the reagents costs are controlled at 22.4 yuan/ton of water.Industrial tests have been carried out on the basis of previous tests to verify the removal of copper by acid sulfuration process.1.87 million yuan have been invested to build acid copper sulfide and cyanide acid recovery system with a daily processing capacity of 4800 m3 water.After commissioning,copper ion in water after treatment was decreased from an average of 217.4 mg/1 to 39.9 mg/1;copper recovery rate was 81.67%.The treatment cost of copper removal by acid sulfuration method is about 5.34 yuan/ton of water.The total value of recovered copper metal and sodium cyanide is about 12.91 yuan/ton of water.The treatment of water per ton can produce 7.57 yuan of income,and good economic benefits have been obtained.In this paper,the optimization direction of heap leaching-adsorption process of oxidized low-grade copper bearing gold ore is put forward,and some achievements have been obtained.It provides reference suggestions for heap leaching process of low-grade copper bearing gold ore,which can be used for reference in similarmines in china. |
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